At one point, the film carried the subtitle "The Future Begins." Coincidentally, the film Star Trek (which opened weeks before Terminator Salvation) used the same saying as a tagline. Actor Anton Yelchin appears in both films.

Old recordings of Sarah Connor are played in the film, with lines nearly word-for-word from The Terminator. Linda Hamilton voiced the lines herself in an uncredited role.

Director McG asked the cast and crew to read the novel The Road by [?] Cormac McCarthy and Do Androids Dream of Electric Sheep? by Philip K. Dick - the basis for Blade Runner - because he wanted them to absorb the bleakness of the world in the novels.